5500 RPM limit?!?!?

Christ · #1 10-21-2007, 10:48 AM

Mmk.. this is wierd... car never used to do this, but has started recently.

A6 cam on B2 head, A6 intake/TB, D15B2 block and bottom end. MPFI swapped W/ PM6 ECU on LX body.

Basically, the car used to kick like hell, but now, it feels like when you get to 5500 RPM, it's limited... it literally won't go past it, starts jerking just like a rev limiter... occaisional O2 sensor code, but it even does it when the sensor isn't acting up...

"seat of the pants" it feels better @ 1/4 or 1/2 throttle than it does @ WOT.
Valve and ignition timing are almost definitely off, going to check those next weekend (next time I see the car), as well as doing a full tune-up, and cleaning the cap/rotor, changing tranny (no RVS).

Anything else I should be checking?

Christ · #2 10-26-2007, 02:36 AM

bump

to see if I can get something to look for here

Tony · #3 10-26-2007, 07:35 AM

Timing is where I would check first, probably jumped somewhere.

turtlecrxsi · #4 10-26-2007, 07:43 AM

Quote:

Originally Posted by Tony

Timing is where I would check first, probably jumped somewhere.

That's what I was thinking.

Christ · #5 10-26-2007, 10:40 AM

I'm gonna check that this weekend... anything else?

The cap and rotor are getting replaced, full tune-up, checking timing, both ignition and valve timing, cuz I know they're both off... the A6 cam, we had trouble figuring out where to line it up for the most high-end... obviously we got it wrong.

turtlecrxsi · #6 10-26-2007, 11:03 AM

I had my a6 cam timed at about -1-0* with my AEM cam gear. It was gutless at high speeds though...

Lordipaq · #7 10-30-2007, 07:57 PM

I had the same problem with my 88 Si. I swapped the ecu and it completely fixed the problem.

Christ · #8 10-31-2007, 11:02 AM

well, you're only looking at making about 108 HP max w/ a A6/MPFI swap., so of course it was gutless... I"m looking at swapping the ECU for a '91 Si version, since I can socket/chip it later.

turtlecrxsi · #9 10-31-2007, 11:21 AM

Quote:

Originally Posted by Dr0pZ0n3

well, you're only looking at making about 108 HP max w/ a A6/MPFI swap., so of course it was gutless... I"m looking at swapping the ECU for a '91 Si version, since I can socket/chip it later.

Actually, it had a little more power than that

...just a little anyway... had regrind cam, a/c delete, race pulleys (the kind Tony was looking for without a/c part), 11.9lb act flywheel, exedy carbon street clutch, tsudo cai, dc ceramic header and full custom exhaust... plus, burnt off undercoating

...oh yeah, and sunroof delete (the whole thing including the motor, brackets, etc. was replaced with sheet metal). Wasn't a hp monster but would boil the tires easily... haha. Before I sold it I left a burnout in front of my old house that left two fat lines for a good 30 feet. Anyway, it would make power all the way to redline at 7200rpms but was still gutless at high speeds...

Christ · #10 10-31-2007, 11:49 AM

probably aero efficiency, would be my guess.

This thing has a A6 cam, B2 block, stage 1 clutch on stock flywheel, stock pulleys, etc. MPFI Si intake swap... stock B2 is 92 HP, I'm assuming 108 would be highest possible figure for the estimated upgrades... 100 would be baseline.

W/ the HF tranny in there, it's really wierd... b/c it goes from full pull to nothing every shift... but it has the torque to keep up right now, and it's getting more as soon as money isn't such an issue... right now I'm having trouble with even registering my car... b/c of money. Rent is due, so yeah.

I'm planning on having the machine shop where i work mill me out some aluminum lightweight race pulleys, and I'm having the stock flywheel shaved to as little as i can get away with.. and soon enough, I"ll be going w/ my 230 HP DOHC ZC turbo build... except I may just say the hell w/ it and delete the turbo, rework the engine when I get it, and go all motor. Still debating that, b/c I have the IHI RHB5 sitting in the house in my toolbox... so I may decide to use it on my tractor.

turtlecrxsi · #11 10-31-2007, 12:44 PM

With those mods and a successful mpfi swap you should be looking at least 108hp. 108hp is stock flywheel hp for the Si set up with A/C etc. If you lessen the rotational mass theoretically you will free up more ponies. Different set-ups do different things though...

Tony · #12 10-31-2007, 12:55 PM

Yea, and I'm still looking for a decent pulley for my D...got the CTR for my B18

Was gonna get the flywheel lightened too, but I'm afraid of getting too much power to the wheels on this CRX since it weighs nothing and will be on dirt.

Christ · #13 11-01-2007, 12:44 AM

Tony, if you lighten the flywheel too much, quick way to take care of the excess engine revvy'ness is to loosen the accelerator pedal cable. just give yourself a lil extra freeplay in that, and get some heavier pulleys, and you'll compensate for a lean flywheel.

Well, I"ll be re-re-re-rewiring the MPFI swap, and taking out all unnecessary wires and everything else, b/c I don't use half the shit in the car.. and I"m more interested in losing a few ounces than having another switch to play with...

I got a new toy at work today.. it's the throttle lever for a John Deere tractor, and I"ll be setting it to 4250 RPM when it's wide open, perfect for launching

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